Athletic footwear sole construction enabling enhanced energy storage, retrieval and guidance

ABSTRACT

Athletic footwear has an upper and sole. The sole has heel and midfoot regions and metatarsel and toe regions which include a foundation layer of semi-flexible material attached to the upper and defining a plurality of stretch chambers, a stretch layer attached to the foundation layer and having portions of elastic stretchable material underlying the stretch chambers of the foundation layer, and a thrustor layer attached to the stretch layer and having portions of stiff material underlying and aligned with the stretch chambers of the foundation layer and with the portions of the stretch layer disposed between the thrustor layer and foundation layer such that interactions can occur between the foundation layer, stretch layer and thrustor layer in response to compressive forces applied thereto upon contact of the heel and midfoot regions and metatarsel and toe regions of the sole with a support surface so as to convert and temporarily store energy applied to heel and midfoot regions and metatarsel and toe regions of the sole by a wearer&#39;s foot into mechanical stretching of the portions of the stretch layer into the stretch chambers. The stored applied energy is thereafter retrieved in the form of rebound of the stretched portions of the stretch layer and portions of the thrustor layer therewith. Whereas components of the heel and midfoot regions of the heel provide temporary storage and retrieval of applied energy at central and peripheral sites underlying the heel and midfoot of the wearer&#39;s foot, components of the metatarsel and toe regions of the sole provide temporary storage and retrieval of applied energy at independent sites underlying the individual metatarsals and toes of the wearer&#39;s foot.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention generally relates to athletic footwear and,more particularly, is concerned with an athletic footwear soleconstruction having a combination of structural features enablingenhanced storage, retrieval and guidance of wearer muscle energy in amanner that complements and augments performance of participants inrecreational and sports activities.

[0003] 2. Description of the Prior Art

[0004] The increasing popularity of athletic endeavors has beenaccompanied by an increasing number of shoe designs intended to meet theneeds of the participants in the various sports. The proliferation ofshoe designs has especially occurred for the participants in athleticendeavors involving walking and running. In typical walking and runninggaits, it is well understood that one foot is on the ground in a “stancemode” while the other foot is moving through the air in a “swing mode”.Furthermore, in the stance mode, the respective foot “on the ground”travels through three successive basic phases; heel strike, mid stanceand toe off.

[0005] Current shoe designs fail to adequately address the needs of theparticipant's foot and ankle system during each of these successivestages. Current shoe designs cause the participant's foot and anklesystem to lose a significant proportion, by some estimates at leastthirty percent, of its functional abilities including its abilities toabsorb shock, load musculature and tendon systems, and to propel therunner's body forward. This is because the soles of current walking andrunning shoe designs fail to address individually the muscles andtendons of a participant's foot. The failure to individually addressthese foot components inhibits the flexibility of the foot and anklesystem, interferes with the timing necessary to optimally load the footand ankle system, and interrupts the smooth and continuous transfer ofenergy from the heel to the toes of the foot during the three successivebasic phases of the “on the ground” foot travel.

[0006] Historically, manufacturers of modern running shoes added foam tocushion a wearer's foot. Then, gradually manufacturers developed otheralternatives to foam-based footwear for the reason that foam becomespermanently compressed with repeated use and thus ceases to perform thecushioning function. The largest running shoe manufacturer, Nike Inc. ofBeaverton, Oreg., has utilized bags of compressed gas as the means tocushion the wearer's foot. A German manufacturer, Puma AG, has proposeda foamless shoe in which polyurethane elastomer is the cushioningmaterial. Another running shoe manufacturer, Reebok International ofStoughton, Mass., recently introduced a running shoe which has twolayers of air cushioning. Running shoe designers heretofore have soughtto strike a compromise between providing enough cushioning to protectthe wearer's heel but not so much that the wearer's foot will wobble andget out of sync with the working of the knee. The Reebok shoe uses airthat moves to various parts of the sole at specific times. For example,when the outside of the runner's heel touches ground, it lands on acushion of air. As the runner's weight bears down, that air is pushed tothe inside of the heel, which keeps the foot from rolling inward toomuch while another air-filled layer is forcing air toward the forefoot.When the runner's weight is on the forefoot, the air travels back to theheel.

[0007] However, no past shoe designs, including the specific ones citedabove, are believed to adequately address the aforementioned needs ofthe participant's foot and ankle system during walking and runningactivities in a manner that augments performance. The past approaches,being primarily concerned with cushioning the impact of the wearer'sfoot with the ground surface, fail to even recognize, let alone begin toaddress, the need to provide features in the shoe sole that will enhancethe storage, retrieval and guidance of a wearer's muscle energy in a waythat will complement and augment the wearer's performance during thewalking, running and jumping activities.

[0008] Consequently, a pressing need still remains for improvements insole construction for athletic footwear that will provide features thatwill enhance energy utilization.

SUMMARY OF THE INVENTION

[0009] The present invention provides an athletic foowear soleconstruction designed to satisfy the aforementioned needs. The athleticfootwear sole of the present invention provides a combination ofstructural features under the heel, midfoot, and forefoot regions of thewearer's foot that enable enhanced storage, retrieval and guidance ofmuscle energy in a manner that complements and augments wearerperformance in sports and recreational activities. The sole constructionof the present invention enables athletic footwear for walking, runningand jumping to improve and enhance performance by complementing,augmenting and guiding the natural flexing actions of the muscles of thefoot. The combination of structural features incorporated in the soleconstruction of the present invention provides unique control over andguidance of the energy of the wearer's foot as it travels through thethree successive basic phases of heel strike, mid stance and toe off.

[0010] Accordingly, the present invention is directed to an athleticfootwear having an upper and sole with the sole having heel, midfoot,metatarsel, and toe regions wherein the sole comprises a foundationlayer of stiff material attached to the upper and defining a pluralityof stretch chambers, a stretch layer attached to the foundation layerand having portions of elastic stretchable material underlying thestretch chambers of the foundation layer, and a thrustor layer attachedto the stretch layer and having portions of stiff material underlyingand aligned with the stretch chambers of the foundation layer and withthe portions of the stretch layer disposed between the thrustor layerand foundation layer. Given the above-defined arrangment, interactionsoccur between the foundation layer, stretch layer and thrustor layer inresponse to compressive forces applied thereto upon contact of the heeland midfoot regions and metatarsel and toe regions of the sole with asupport surface so as to convert and temporarily store energy applied toheel and midfoot regions and metatarsel and toe regions of the sole by awearer's foot into mechanical stretching of the portions of the stretchlayer into the stretch chambers of the foundation layer. The storedapplied energy is thereafter retrieved in the form of rebound of thestretched portions of the stretch layer and portions of the thrustorlayer therewith. Whereas components of the heel and midfoot regions ofthe sole provide temporary storage and retrieval of applied energy atcentral and peripheral sites underlying the heel and midfoot of thewearer's foot, components of the metatarsel and toe regions of the soleprovide the temporary storage and retrieval of applied energy atindependent sites underlying the individual metatarsals and toes of thewearer's foot.

[0011] These and other features and advantages of the present inventionwill become apparent to those skilled in the art upon a reading of thefollowing detailed description when taken in conjunction with thedrawings wherein there is shown and described an illustrative embodimentof the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

[0012] In the following detailed description, reference will be made tothe attached drawings in which:

[0013]FIG. 1 is a side elevational view of an athletic footwear soleconstruction of the present invention.

[0014]FIG. 2 is a front elevational view of the sole construction.

[0015]FIG. 3 is an exploded top perspective view of heel and midfootregions of the sole construction of the present invention.

[0016]FIG. 4 is an exploded bottom perspective view of heel and midfootregions of the sole construction.

[0017]FIG. 5 is a rear end view of the heel region of the soleconstruction shown in a relaxed condition.

[0018]FIG. 6 is a vertical transverse sectional view of the soleconstruction of FIG. 5.

[0019]FIG. 7 is a rear end view of the heel region of the soleconstruction shown in a loaded condition.

[0020]FIG. 8 is a vertical transverse sectional view of the soleconstruction of FIG. 7.

[0021]FIG. 9 is an exploded top perspective view of the metatarsel andtoe regions of the sole construction of the present invention.

[0022]FIG. 10 is a vertical transverse sectional view of the metatarselregion of the sole construction shown in a relaxed condition.

[0023]FIG. 11 is a vertical transverse sectional view of the metatarselregion of the sole construction shown in a loaded condition.

DETAILED DESCRIPTION OF THE INVENTION

[0024] Referring to the drawings and particularly to FIGS. 1 and 2,there is illustrated an article of athletic footwear for walking,running, and/or jumping, being generally designated 10. The footwear 10includes an upper 12 and a sole 14 having heel and midfoot regions 14A,14B and metatarsel and toe regions 14C, 14D wherein are provided thestructural features of the sole 14 constituting the present invention.The sole 14 incorporating the construction of the present inventionimproves the walking, running and jumping performance of a wearer of thefootwear 10 by providing a combination of structural features whichcomplements and augments, rather than resist, the natural flexingactions of the muscles of the foot to more efficiently utilize themuscular energy of the wearer.

[0025] Referring to FIGS. 1 and 3 to 8, the heel and midfoot regions14A, 14B of the sole 14 basically includes the stacked combination of afootbed layer 16, an upper stretch layer 18, an upper thrustor layer 20,a lower stretch layer 22, and a lower thrustor layer 24. The footbedlayer 16 of the sole 14 serves as a foundation for the rest of thestacked components of the heel and midfoot regions 14A, 14B. The footbedlayer 16 includes a substantially flat foundation plate 26 of semi-rigidsemi-flexible thin stiff material, such as fiberglass, whose thicknessis chosen to predetermine the degree of flexion (or bending) it canundergo in respose to the load that will be applied thereto.

[0026] The foundation plate 26 has a heel portion 26A and a midfootportion 26B. The foundation plate 26 has a continuous interior lip 26Cencompassing a central opening 28 formed in the foundation plate 26which provides its heel portion 26A with a generally annular shape. Theflat foundation plate 26 also has a plurality of continuous interioredges 26D encompassing a corresponding plurality of elongated slots 30formed in the foundation plate 26 arranged in spaced apart end-to-endfashion so as to provide a U-shaped pattern of the slots 30 startingfrom adjacent to a forward end 26E of the foundation plate 26 andextending rearwardly therefrom and around the central opening 28. Theslots 30 are slightly curved in shape and run along a periphery 26F ofthe foundation plate 26 but are spaced inwardly from the periphery 26Fthereof and outwardly from the central opening 28 thereof so as to leavesolid narrow borders respectively adjacent to the periphery 26F and thecentral opening 28 of the foundation plate 26. The slots 30 alone or inconjunction with recesses 32 of corresponding shape and position in thebottom of the shoe upper 12 define a corresponding plurality ofperipheral stretch chambers 34 in the foundation plate 26.

[0027] The upper stretch layer 18 is made of a suitable elasticmaterial, such as rubber, and includes a flexible substantially flatstretchable body 36 and a plurality of compressible lugs 38 formed onand projecting downwardly from the bottom surface 36A of the flatstretchable body 36 at the periphery 36B thereof. The peripheral profileof the flat stretchable body 36 of the upper stretch layer 18 generallymatches that of the flat foundation plate 26 of the footbed layer 16. Inthe exemplary embodiment shown in FIGS. 1, 3, and 5 to 8, thecompressible lugs 38 are arranged in a plurality of pairs thereof, suchas six in number, spaced apart along opposite lateral sides of the flatstretchable body 36. Other arrangements of the compressible lugs 38 arepossible so long as it adds stability to the sole 14. For ease ofmanufacture, the compressible lugs 38 are preferably integrally attachedto the flat stretchable body 36.

[0028] The upper thrustor layer 20 disposed below and aligned with theupper stretch layer 18 includes a substantially flat support plate 40preferably made of a a relatively incompressible, semi-rigidsemi-flexible thin stiff material, such as fiberglass, having aconstruction similar to that of the flat foundation plate 26 of thefootbed layer 16. The flat support plate 40 has a heel portion 40A and amidfoot portion 40B. The support plate 40 also has a continuous interiorrim 40C surrounding a central hole 42 formed through the support plate40 which provides its heel portion 40A with a generally annular shape.The central hole 42 provides an entrance to a space formed between theflat stretchable body 36 of the upper stretch layer 18 and the flatsupport plate 40 spaced therebelow which space constitutes a maincentral stretch chamber 44 of said sole 14. The peripheral profile ofthe upper thrustor layer 20 generally matches the peripheral profiles ofthe footbed layer 16 and upper stretch layer 18 so as to provide thesole 14 with a common profile when these components are in an operativestacked relationship with one on top of the other.

[0029] The upper thrustor layer 20 also includes a plurality ofstretch-generating thrustor lugs 46 made of a relatively incompressibleflexible material, such as plastics, and being mounted on the topsurface 40D of the flat support plate 40 and projecting upwardlytherefrom so as to space the flat support plate 40 below the flatstretchable body 36 of the upper stretch layer 18. The thrustor lugs 46are arranged in a spaced apart end-to-end fashion which corresponds tothat of the slots 30 in the foundation plate 26 so as to provide aU-shaped pattern of the thrustor lugs 46 starting from adjacent to aforward end 40E of the flat support plate 40 and extending rearwardtherefrom and around the central opening 42. The thrustor lugs 46 runalong a periphery 40F of the support plate 40 but are spaced inwardlytherefrom and outwardly from the central opening 42 of the support plate40 so as to leave solid narrow borders respectively adjacent to theperiphery 40F and the central opening 42 of the support plate 40. Theperipherally-located thrustor lugs 46 thus correspond in shape andposition to the peripherally-located slots 30 in the flat foundationplate 26 of the footbed layer 16 defining the peripherally-locatedstretch chambers 34. For ease of manufacture the thrustor lugs 46 areattached to a common thin sheet which, in turn, is adhered to the topsurface 40D of the flat support plate 40.

[0030] The flat support plate 40 of the upper thrustor layer 20 supportsthe thrustor lugs 46 in alignment with the slots 30 and thus with theperipheral stretch chambers 34 of the foundation plate 26 and upper 12of the shoe 10. However, the flat stretchable body 36 of upper stretchlayer 18 is disposed between the stretch-generating thrustor lugs 46 andflat foundation plate 26. Thus, with the footbed layer 16, upper stretchlayer 18 and upper thrustor layer 20 disposed in the operative stackedrelationship with one on top of the other in the heel and midfootregions 14A, 14B of the sole 14, spaced portions 36C of the flatstretchible body 36 of the upper stretch layer 18 overlie top ends 46Aof the stretch-generating thrustor lugs 46 and underlie the peripheralstretch chambers 34. Upon compression of the footbed layer 16 and upperthrustor layer 20 toward one another from a relaxed condition shown inFIGS. 5 and 6 toward a loaded condition shown in FIGS. 7 and 8, asoccurs upon impact of the heel and midfoot regions 14A, 14B of the sole14 of the shoe 10 with a support surface, the spaced portions 36A of theflat stretchable body 36 are forceably stretched by the upwardlymovement of the top ends 46A of the thrustor lugs 46 upwardly past theinterior edges 26D of the foundation plate 26 surrounding the slots 30and into the stretch chambers 34. This can occur due to the fact thatthe thrustor lugs 46 are enough smaller in their footprint size thanthat of the slots 30 so as to enable their top ends 46A together withthe portions 36A of the flat stretchable body 36 stretched over the topends 46A of the thrustor lugs 46 to move and penetrate upwardly throughthe slots 30 and into the peripheral stretch chambers 34, as shown inFIGS. 7 and 8.

[0031] The compressible lugs 38 of the upper stretch layer 18 arelocated in alignment with the solid border extending along the periphery26F of the foundation plate 26 outside of the thrustor lugs 46. Thecompressible lugs 38 project downwardly toward the support base 40. Thecompressive force applied to the foundation plate 26 of the footbedlayer 16 and to the support plate 42 of the upper thrustor layer 20,which occurs during normal use of the footwear 10, causes compression ofthe compressible lugs 38 from their normal tapered shape assumed in therelaxed condition of the sole 14 shown in FIGS. 5 and 6, into the bulgedshape taken on in the loaded condition of the sole 14 shown in FIGS. 7and 8. In addition to adding stability, the function of the compressiblelugs 38 is to provide storage of the energy that was required tocompress the lugs 38 and thereby to quicken and balance the resistanceand rebound qualities of the sole 14.

[0032] As can best be seen in FIGS. 1 and 3, the stretch-generatingthrustor lugs 46 are generally greater in height at the heel portion 40Aof the support plate 40 than at the midfoot portion 40B thereof. Thisproduces a wedge shape through the heel and midfoot regions 14A, 14B ofthe sole 14 from rear to front, that effectively generates and guides aforward and upward thrust for the user's foot as it moves through heelstrike to mid stance phases of the foot's “on the ground” travel.

[0033] Referring to FIGS. 2, 3, and 8, the lower stretch layer 22 is inthe form of a flexible thin substantially flat stretchable sheet 48 ofresilient elastic material, such as rubber, attached in any suitablemanner, such as by gluing, to a bottom surface 40G of the flat supportplate 40 of the upper thruster layer 20. The lower thrustor layer 24disposed below the flat stretchable sheet 48 of the lower stretch layer22 includes a thrustor plate 50, a thrustor cap 52 and a retainer ring54. The thrustor plate 50 preferably is made of a suitable semi-rigidsemi-flexible thin stiff material, such as fiberglass. The thrustorplate 50 is bonded to the bottom surface of a central portion 48A of thestretchable sheet 48 in alignment with the central hole 42 in thesupport plate 40 of the upper thrustor layer 20. In operative stackedrelationsip of the stretchable sheet 48 of the lower stretch layer 22between the stretch-generating thrustor plate 50 of the lower thrustorlayer 24 and the support plate 40 of the upper thrustor layer 20, theperiphery 48B of the central portion 48A of the stretchable sheet 48overlies the peripheral edge 50A of the stretch-generating thrustorplate 50 and underlie the rim 40C of the support plate 40.

[0034] Upon compression of the lower thrustor layer 24 toward the upperthrustor layer 20 from a relaxed condition shown in FIGS. 5 and 6 towarda loaded condition shown in FIGS. 7 and 8, as occurs upon impact of theheel and midfoot regions 14A, 14B of the sole 14 of the shoe 10 with asupport surface during normal activity, the periphery 48B of thestretchable sheet 48 is forceably stretched by the peripheral edge 50Aof the thrustor plate 50 upwardly past the rim 40C surrounding thecentral hole 42 and into the main central stretch chamber 44. This canoccur due to the fact that the thrustor plate 50 is enough smaller inits footprint size than that of the central hole 42 in the support plate40 so as to enable the thrustor plate 50 together with the periphery 48Bof the central portion 48A of the stretchable sheet 48 stretched overthe thrustor plate 50 to move and penetrate upwardly through the centralhole 42 and into the main centrally-located stretch chamber 44, as shownin FIGS. 7 and 8.

[0035] The rigidity of the thrustor plate 50 of the lower thrustor layer24 encourages a stable uniform movement and penetration of the thrustorplate 50 and resultant stretching of the periphery 48B of the centralportion 48A of the stretchable sheet 48 into the main central stretchchamber 44 in response to the application of compressive forces. Thethrustor cap 52 is bonded on the bottom surface 50A of the thrustorplate 50 and preferably is made of a flexible plastic or hard rubber andits thickness partially determines the depth of penetration and lengthof drive or rebound of the thrustor plate 50. The ground engagingsurface 52A of the thrustor cap 52 is generally domed shape and presentsa smaller footprint than that of the thrustor plate 50. The retainerring 54 is preferably made of the same material as the thrustor plate 50and surrounds the thrustor plate 50 and thrustor cap 52. The retainerring 54 is bonded on the bottom surface of the stretchable sheet 48 inalignment with the central hole 42 in the support plate 40 and surroundsthe thrustor plate 50 so as to increase the stretch resistance of thecentral portion 48A of the stretchable sheet 48 and stabilize the lowerthrustor layer 24 in the horizontal plane reducing the potential ofjamming or binding of the thrustor plate 50 as it stretches theperiphery 48B of the central portion 48A of the stretchable sheet 48through the central hole 42 in the flat support plate 40 of the upperthrustor layer 20.

[0036] The above-described centrally-located interactions in the heeland midfoot regions 14A, 14B of the sole 14 between the support plate 40of the upper thrustor layer 20, the flat stretchable sheet of the lowerstretch layer 22 and flat thrustor plate of the lower thrustor layer 24of the heel and midfoot regions 14A, 14B occur concurrently andinterrelatedly with the peripherally-located interactions betweenfootbed layer 16, the flat stretchable body 36 of the upper stretchlayer 18 and the thrustor lugs 46 of the upper thrustor layer 20. Theseinterrelated central and peripheral interactions convert the energyapplied to the heel and midfoot regions 14A, 14B of the sole 14 by thewearer's foot into mechanical stretch. The applied energy is thustemporarily stored in the form of concurrent mechanical stretching ofthe central portion 48A of the lower stretchable sheet 48 of the lowerstretch layer 22 and of the spaced portions 36C of the upper stretchablebody 36 of the upper stretch layer 18 at the respective sites of thecentrally-located and peripherally-located stretch chambers 44, 34. Thestored applied energy is thereafter retrieved in the form of concurrentrebound of the stretched portions 36C of the upper stretchable body 36and the thrustor lugs 46 therewith and of the stretched portion 48A ofthe lower stretchable sheet 48 and the thrustor plate 40 therewith. Theresistance and speed of these stretching and rebound interactions isdetermined and controlled by the size relationship between the retainerring 54 and the rim 40C about the central hole 42 of the support plate49 and between the top ends 46A of the thrustor lugs 46 and thecontinuous interior edges 26D encompassing the slots 30 of thefoundation plate 26. The thickness and elastic qualities preselected forthe lower stretchable sheet 48 of the lower stretch layer 22 and theupper stretchable body 36 of the upper stretch layer 18 influence andmediate the resistance and speed of these interactions. The stretchingand rebound of the lower stretchable sheet 48 also causes a torquing ofthe support plate 40. The torquing can be controlled by the thickness ofthe support plate 40 as well as by the size and thickness of theretainer ring 54.

[0037] Referring to FIG. 3, the midfoot region 14B of the sole 14 of thepresent invention also includes a curved midfoot piece 56 and acompression midfoot piece 58 complementary to the curved midfoot piece56. The midfoot portion 26B of the foundation plate 26 terminates at theforward end 26E which has a generally V-shaped configuration. The curvedmidfoot piece 56 preferably is made of graphite and is provided as acomponent separate from the foundation plate 26. The curved midfootpiece 56 has a configuration which is complementary to and fits with theforward end 26E of the foundation plate 26. The forward end 26E of thefoundation plate 26 cradles the number five metatarsal bone of theforefoot as the curved midfoot piece 56 couples the heel and forefootportions 14A, 14B of the sole 14 so as to load the bones of the forefootin an independent manner. The peripheral profiles of the upper stretchlayer 18 and compression midfoot piece 58 are generally the same asthose of the foundation plate 26 and curved midfoot piece 56.

[0038] Referring now to FIGS. 1, 2, and 9 to 11, the metatarsel and toeregions 14C, 14D of the sole 14 basically include the stackedcombinations of metatarsel and toe articulated plates 60A, 60B,metatarsel and toe foundation plates 62A, 62B, a common metatarsel andtoe stretch layer 64, and metatarsel and toe thrustor layers 65A, 65B.The metatarsel and toe thrustor layers 65A, 65B include metatarsel andtoe plates 66A, 66B, metatarsel and toe thrustor caps 68A, 68B andmetatarsel and toe retainer rings 70A, 70B. Except for a common stretchlayer 64 serving both metatarsel and toe regions 14C, 14D of the sole14, there is one stacked combination of components in the metatarselregion 14C of the sole 14 that underlies the five metatarsals of thewearer's foot and another separate stacked combination of components inthe toe region 14D of the sole 14 that underlies the five toes of thewearer's foot. Except for the upper articulated plates 60A, 60B, theabove-mentioned stacked combinations of components of the metatarsel andtoe regions 14C, 14D of the sole 14 interact (stretching and rebound)generally similarly to the above-described interaction (stretching andrebound) of the stacked combination of components of the heel andmidfoot regions 14A, 14B of the sole 14. However, whereas the stackedcombination of components of the heel and midfoot regions 14A, 14Bprovide interrelated main and peripheral sites for temporary storage andretrieval of the applied energy, the stacked combination of componentsof the metatarsel and toe regions 14C, 14D provide a plurality ofrelatively independent sites for temporary storage and retrieval of theapplied energy at the individual metatarsals and toes of the wearer'sfoot. The additional components, namely, the articulated plates 60A,60B, of the metatarsel and toe regions 14C, 14D each has a plurality oflaterally spaced slits 72A, 72B formed therein extending from theforward edges 74A, 74B rearwardly to about midway between the forwardedges 74A, 74B and rearward edges 76A, 76B of the articulated plates60A, 60B. These pluralities of spaced slits 72A, 72B define independentdeflectable or articulatable appendages 78A, 78B on the metatarsel andtoe articulated plates 60A, 60B that correspond to the individualmetatarsels and toes of the wearer's foot and overlie and augment theindependent characteristic of the respective sites of temporary storageand retrieval of the applied energy at the individual metatarsals andtoes of the wearer's foot.

[0039] More particularly, the metatarsel and toe articulated plates 60A,60B are substantially flat and made of a suitable semi-rigidsemi-flexible thin stiff material, such as graphite, while themetatarsel and toe foundation plates 62A, 62B disposed below themetatarsel and toe articulated plates 60A, 60B are substantially flatand made of a incompressible flexible material, such as plastic. Each ofthe metatarsel and toe foundation plates 62A, 62B has a continuousinterior edge 80A, 80B defining a plurality of interconnected interiorslots 82A, 82B which are matched to the metatarsels and toes of thewearer's foot. The continuous interior edges 80A, 80B are spacedinwardly from located inwardly from the peripheries 84A, 84B of themetatarsel and toe foundation plates 62A, 62B so as to leave continoussolid narrow borders 86A, 86B respectively adjacent to the peripheries84A, 84B. The metatarsel and toe portions of the borders 86A, 86Bencompassing or outlining the locations of the separate metatarsels andtoes of the wearer's foot and of the appendages 78A, 78B on thearticulated plates 60A, 60B are also separated by narrow slits 88A, 88B.The pluralities of interconnected interior slots 82A, 82B definecorresponding pluralities of metatarsel and toe stretch chambers 90A,90B in the respective metatarsel and toe foundation plates 62A, 62B.

[0040] The common metatarsel and toe stretch layer 64 is made of asuitable elastic stretchable material, such as rubber, and is disposedbelow the metatarsel and toe foundation plates 62A, 62B. The peripheralprofile of the common stretch layer 64 generally matches the peripheralprofiles of the articulated plates 60A, 60B and of the foundation plates62A, 62B so as to provide the sole 14 with a common profile when thesecomponents are in an operative stacked relationship with one on top ofthe other. The common stretch layer 64 is attached at its upper surface64A to the respective continuous bordens 86A, 86B of the foundationplates 62A, 62B between their respective continuous interior edges 80A,80B and peripheries 84A, 84B.

[0041] The metatarsel and toe thrustor plates 66A, 66B are disposedbelow and aligned with the common stretch layer 64 and the pluralitiesof interconnected interior slots 82A, 82B in foundation plates 62A, 62Bforming the metatarsel and toe stretch chambers 90A, 90B. The metatarseland toe thrustor plates 66A, 66B are made of semi-rigid semi-flexiblethin stiff material, such as fiberglass. The metatarsel and toe thrustorplates 66A, 66B are bonded to the lower surface 64B of the commonstretch layer 64 in alignment with the pluralities of interconnectedinterior slots 82A, 82B of forming the metatarsel and toe stretchchambers 90A, 90B of the foundation plates 62A, 62B. In the operativestacked relationsip of the common stretch layer 64 between thestretch-generating metatarsel and toe thrustor plates 66A, 66B and therespective metatarsel and toe foundation plates 62A, 62B, portions 92A,92B of the common stretch layer 64 overlie the peripheral edges 94A, 94Bof the metatarsel and toe thrustor plates 66A, 66B and underlie thecontinuous interior edges 80A, 80B of the metatarsel and toe foundationplates 62A, 62B.

[0042] Upon compression of the lower metatarsel and toe thrustor plates66A, 66B toward the upper metatarsel and toe foundation plates 62A, 62Bfrom a relaxed condition shown in FIG. 13 toward a loaded conditionshown in FIG. 14, as occurs upon impact of the metatarsel and toeregions 14C, 14D of the sole 14 of the shoe 10 with a support surfaceduring normal activity, the portions 92A, 92B of the common stretchlayer 64 are forceably stretched by the peripheries 94A, 94B of themetatarsel and toe thrustor plates 66A, 66B upwardly past the continuousinterior edges 80A, 80B of the metatarsel and toe foundation plates 62A,62B into the metatarsel and toe stretch chambers 90A, 90B. This canoccur due to the fact that the metatarsel and toe thrustor plates 66A,66B are enough smaller in their respective footprint sizes than thesizes of the slots 82A, 82B in the metatarsel and toe foundation plates62A, 62B so as to enable the metatarsel and toe thrustor plates 66A, 66Btogether with the portions 92A, 92B of the common stretch layer 64stretched over the respective thrustor plates 66A, 66B to move andpenetrate upwardly through the slots 82A, 82B and into the metatarseland toe stretch chambers 90A, 90B, as shown in FIG. 14.

[0043] The rigidity of the metatarsel and toe thrustor plates 66A, 66Bencourages a stable uniform movement and penetration of the thrustorplates 66A, 66B and resultant stretching of the portions 92A, 92B of thecommon stretch layer 64 into the metatarsel and toe stretch chambers90A, 90B in response to the application of compressive forces. Themetatarsel and toe thrustor caps 68A, 68B are bonded respectively on thebottom surfaces 96A, 96B of the metatarsel and toe thrustor plates 66A,66B and preferably is made of a flexible plastic or hard rubber andtheir respective thicknesses partially determine the depth ofpenetration and length of drive or rebound of the metatarsel and toethrustor plates 66A, 66B. The metatarsel and toe retainer rings 70A, 70Bare preferably made of the same material as the metatarsel and toethrustor plates 66A, 66B and surround the respective thrustor plates66A, 66B and thrustor caps 68A, 68B. The metatarsel and toe retainerrings 70A, 70B are bonded on the lower surface 64B of the common stretchlayer 64 in alignment with the interior slots 82A, 82B and surround thethrustor plates 66A, 66B so as to increase the stretch resistance of theportion 92A, 92B of the common stretch layer 64 and stabilize themetatarsel and toe thrustor plates 66A, 66B in the horizontal planereducing the potential of jamming or binding of the thrustor plates 66A,66B as they stretch the peripheries of the portions 92 a, 92B of thecommon stretch layer 64 into the metatarsel and toe stretch chambers90A, 90 b in the metatarsel and toe foundation plates 62A, 62B.

[0044] The above-described plurality of stretching interactions betweenthe metatarsel and toe foundation plates 62A, 62B, common stretch layer64 and metatarsel and toe thrustor plates 66A, 66B of the metatarsel andtoe regions 14C, 14D in their stacked relationship converts the energyapplied to the metatarsels and toes by the wearer's foot into mechanicalstretch. The applied energy is stored in the form of mechanicalstretching of the metatarsel and toe portions 92A, 92B of the commonstretch layer 64 at the respective sites of the metatarsel and toestretch chambers 90A, 90B. The applied energy is retrieved in the formof rebound of the stretched portions 92A, 92B of the common stretchlayer 64 and the thrustor plates 66A, 66 b therewith. The resistance andspeed of these stretching interactions is determined and controlled bythe size relationship between the retainer rings 70A, 70B and thecontinuous interior edges 80A, 80B in the metatarsel and toe foundationplates 62A, 62B. The thickness and elastic qualities preselected for thecommon stretch layer 64 influence and mediate the resistance and speedof these interactions. The peripheral profiles of the metatarsel and toethrustor plates 66A, 66B are generally the same. The previouslydescribed midfoot pieces 56, 58 also provide a bridge between thecomponents of the heel and midfoot regions 14A, 14B of the sole 14 andthe components of the metatarsel and toe regions 14C, 14D of the sole14.

[0045] Preliminary experimental treadmill comparative testing of askilled runner wearing prototype footwear 10 having soles 14 constructedin accordance with the present invention with the same runner wearingpremium quality conventional footwear, has demonstrated a significantlyimproved performance of the runner while wearing the prototype footwearin terms of the runner's oxygen intake requirements. The prototypefootwear 10 compared to the conventional footwear allowed the runner touse from ten to twenty percent less oxygen running at the same treadmillspeed. The dramatically reduced oxygen intake requirement can only beattributed to an equally dramatic improvement of the energy efficiencythat the runner experienced while wearing the footwear 10 having theheel construction of the present invention. It is reasonable to expectthat this dramatic improvement in energy efficiency will translate intodramatic improvement in runner performance as should be reflected inelapsed times recorded in running competitions.

[0046] It is thought that the present invention and its advantages willbe understood from the foregoing description and it will be apparentthat various changes may be made thereto without departing from thespirit and scope of the invention or sacrificing all of its materialadvantages, the form hereinbefore described being merely preferred orexemplary embodiment thereof.

I claim:
 1. In an athletic footwear having an upper and sole, said solehaving heel and midfoot regions and metatarsel and toe regions whereinsaid sole comprises: (a) a foundation layer of semi-flexible materialattached to said upper and defining a plurality of stretch chambers; (b)a stretch layer attached to said foundation layer and having portions ofelastic stretchable material underlying the stretch chambers of saidfoundation layer; and (c) a thrustor layer attached to said stretchlayer and having portions of stiff material underlying and aligned withsaid stretch chambers of said foundation layer and with said portions ofsaid stretch layer disposed between said thrustor layer and foundationlayer such that interactions can occur between said foundation layer,stretch layer and thrustor layer in response to compressive forcesapplied thereto upon contact of said heel and midfoot regions and saidmetatarsel and toe regions of said sole with a support surface so as toconvert and temporarily store energy applied to said heel and midfootregions and said metatarsel and toe regions of said sole by a wearer'sfoot into mechanical stretching of said portions of said stretch layerinto said stretch chambers, said stored applied energy thereafter beingretrieved in the form of rebound of said stretched portions of saidstretch layer and portions of said thrustor layer therewith.
 2. The soleof claim 1 wherein said stretch chambers of said heel and midfootregions of said sole are so located to provide said temporary storageand retrieval of applied energy at central and peripheral sitesunderlying the heel and midfoot of a wearer's foot.
 3. The sole of claim2 wherein said stretch chambers of said metatarsel and toe regions ofsaid sole are so located to provide said temporary storage and retrievalof applied energy at independent sites underlying the individualmetatarsals and toes of a wearer's foot.
 4. The sole of claim 1 whereinsaid stretch chambers of said metatarsel and toe regions of said soleare so located to provide said temporary storage and retrieval ofapplied energy at independent sites underlying the individualmetatarsals and toes of a wearer's foot.
 5. In an athletic footwearhaving an upper and a sole, said sole having heel and midfoot regionswherein said sole comprises: (a) a foundation layer made of asemi-flexible material, attached to said upper, and defining a pluralityof peripherally-located stretch chambers underlying a heel and midfootof a wearer's foot; (b) a stretch layer attached to said foundationlayer and having portions made of elastic stretchable materialunderlying said peripherally-located stretch chambers of said foundationlayer; and (c) a thrustor layer attached to said stretch layer andhaving thrustor portions made of stiff material underlying and alignedwith said peripherally-located stretch chambers of said foundation layerand with said portions of said stretch layer disposed between saidthrustor layer and said foundation layer such that interactions canoccur between said upper layer, stretch layer and thrustor layer inresponse to compressive forces applied thereto upon contact of said heeland midfoot regions of said sole with a support surface so as to convertand temporarily store energy applied to said heel and midfoot regions ofsaid sole by a wearer's foot into mechanical stretching of said portionsof said stretch layer into said peripherally-located stretch chambers,said stored applied energy being thereafter retrieved in the form ofrebound of said stretched portions of said stretch layer and saidthrustor portions of said thrustor layer therewith.
 6. The sole of claim5 wherein said peripherally-located stretch chambers are defined by aplurality of elongated slots formed in a spaced apart end-to-endgenerally U-shaped arrangement in said foundation layer.
 7. The sole ofclaim 6 wherein said stretch layer include a flexible substantially flatstretchable body and a plurality of compressible lugs formed on andprojecting downwardly from said flat stretchable body at the peripherythereof to said thruster layer.
 8. The sole of claim 6 wherein saidthrustor layer includes a substantially flat support plate and aplurality of stretch-generating thrustor lugs formed on and projectingupwardly from said support plate at the periphery thereof and definingsaid thrustor portions of said thrustor layer, said stretch-generatingthrustor lugs being disposed in a spaced apart end-to-end arrangementcorresponding to and in alignment with said slots in said foundationplate and thus with said peripherally-located stretch chambers definedby said slots such that upon compression of said foundation layer andthrustor layer toward one another from a relaxed condition toward aloaded condition as occurs upon impact of said heel and midfoot regionsof said sole of said footwear with a support surface, spaced portions ofsaid flat stretchable body are forceably stretched by movement of saidthrustor lugs upwardly toward and into said peripherally-located stretchchambers.
 9. The sole of claim 8 wherein said thrustor lugs having afootprint size smaller than that of said slots so as to enable saidthrustor lugs together with said stretchable portions of said flatstretchable body to move and penetrate and stretch upwardly through saidslots and into said peripherally-located stretch chambers.
 10. The soleof claim 8 wherein said compressible lugs of said stretch layer arelocated in alignment with said support plate outside of said thrustorlugs and projecting downwardly toward said support plate such thatcompressive force applied to said foundation layer and thrustor layercauses compression of said compressible lugs from an uncompressedcondition into a compressed condition in balancing resistance andrebound qualities of said heel and midfoot regions of said heel.
 11. Thesole of claim 8 wherein said stretch-generating thrustor lugs aregenerally greater in height at a heel portion of said support plate thanat a midfoot portion thereof so as to produce a wedge shape from saidheel region to said midfoot region of said sole for effectivelygenerating and guiding a forward and upward thrust for the user's foot.12. In an athletic footwear having an upper and a sole, said sole havingheel and midfoot regions wherein said sole comprises: (a) a foundationlayer made of a semi-flexible material, attached to said upper, anddefining a centrally-located stretch chamber underlying a heel of awearer's foot; (b) a stretch layer attached to said foundation layer andhaving a central portion made of elastic stretchable material underlyingsaid centrally-located stretch chamber of said foundation layer; and (c)a thrustor layer attached to said stretch layer and having a centralthrustor portion made of stiff material underlying and aligned with saidcentrally-located stretch chamber of said foundation layer and with saidcentral portion of said stretch layer disposed between said thrustorlayer and said foundaton layer such that interaction can occur betweensaid foundation layer, stretch layer and thrustor layer in response tocompressive forces applied thereto upon contact of said heel and midfootregions of said sole with a support surface so as to convert and storeenergy applied to said heel and midfoot regions of said sole by awearer's foot into mechanical stretching of said central portion of saidstretch layer into said centrally-located stretch chamber, said storedapplied energy being thereafter retrieved in the form of rebound of saidstretched central portion of said stretch layer and said thrustorportion of said thrustor layer therewith.
 13. The sole of claim 12wherein said foundation layer has a central hole defined thereinproviding an entrance to a space constituting said centrally-locatedstretch chamber.
 14. The sole of claim 13 wherein said stretch layer isin the form of a flexible thin substantially flat stretchable sheetattached to a bottom surface of said foundation layer and extendingacross said central hole defined therein.
 15. The sole of claim 14wherein said thrustor layer is disposed below said flat stretchablesheet and includes a thrustor plate having a peripheral profile matchingthat of said central hole of said foundation layer and attached to abottom surface of a central portion of said stretchable sheet inalignment with said central hole in said foundation layer such that uponcompression of said thrustor layer toward said foundation layer from arelaxed condition toward a loaded condition of said sole, as occurs uponimpact of said heel and midfoot regions of said sole of said footwearwith the support surface during normal activity, said central portion ofsaid stretchable sheet is forceably stretched by said thrustor layerupwardly into said centrally-located stretch chamber.
 16. The sole ofclaim 15 wherein said thrustor layer further includes a thrustor capattached on a bottom surface of said thrustor plate and made of aflexible material, said thrustor cap having a thickness selected to atleast partially determine depth of penetration and length of drive andrebound of said thrustor plate.
 17. The sole of claim 16 wherein saidthrustor cap has a ground engaging surface generally of domed shape andpresenting a smaller footprint than that of said thrustor plate.
 18. Thesole of claim 15 wherein said thrustor layer further includes a retainerring surrounding said thrustor plate and thrustor cap, said retainerring being attached to a bottom surface of said stretchable sheetoutside of said periphery of and surrounding said thrustor plate so asto increase the stretch resistance of said central portion of saidstretchable sheet and stabilize said lower thrustor layer in ahorizontal plane reducing the potential of binding of said thrustorplate as it stretches said central portion of said stretchable sheetthrough said central hole in said foundation layer of said thrustorlayer and into said centrally-located stretch chamber.
 19. In anathletic footwear having an upper and a sole, said sole having heel andmidfoot regions wherein said sole comprises: (a) a footbed layer made ofa semi-flexible material, attached to said upper, and defining aplurality of peripherally-located stretch chambers underlying a heel andmidfoot of a wearer's foot; (b) an upper stretch layer attached to saidfootbed layer and having portions made of elastic stretchable materialunderlying said peripherally-located stretch chambers of said footbedlayer; (c) an upper thrustor layer attached to said upper stretch layerand having peripheral portions made of stiff material underlying andaligned with said peripherally-located stretch chambers of said footbedlayer and with said portions of said upper stretch layer disposedbetween said upper thrustor layer and said footbed layer, said upperthrustor layer also having a central hole formed therein defining acentrally-located stretch chamber underlying the heel of the wearer'sfoot; (d) a lower stretch layer attached to said upper thrustor layerand having a central portion made of elastic stretchable material andunderlying said centrally-located stretch chamber of said upper thrustorlayer; and (e) a lower thrustor layer attached to said lower stretchlayer and having a central thruster portion made of stiff materialunderlying and aligned with said centrally-located stretch chamber ofsaid upper thrustor layer and with said central portion of said lowerstretch layer disposed between said lower thrustor layer and said upperthrustor layer such that interaction in said heel and midfoot regions ofsaid sole between said upper thrustor layer, lower stretch layer andlower thrustor layer occur concurrently with interactions between saidfootbed layer, upper stretch layer and upper thrustor layer in responseto compressive forces applied thereto upon contact of said heel andmidfoot regions of said sole with a support surface so as to convert andstore energy applied to said heel and midfoot regions of said sole by awearer's foot into concurrent mechanical stretching of said centralportion of said lower stretch layer and of said spaced portions of saidupper stretch layer respectively in said centrally-located andperipherally-located stretch chambers, said stored applied energy isthereafter retrieved in the form of concurrent rebound of said stretchedcentral portion of said lower stretch layer and said central thrustorportion of said lower thrustor layer and of said stretched spacedperipheral portions of said upper stretch layer and said peripheralthrustor portions therewith.
 20. The sole of claim 19 wherein saidfootbed layer, upper stretch layer, upper thrustor layer, lower stretchlayer and lower thrustor layer are provided in the aforesaid sequence invertically stacked arrangement with said footbed layer located closestto said upper of said footwear and said lower thrustor layer locatedfarthest from said upper of said footwear.
 21. In an athletic footwearhaving an upper and sole, said sole having metatarsel and toe regionswherein said sole comprises: (a) a pair of foundation layers each madeof semi-flexible material, attached to said upper and defining aplurality of stretch chambers respectively underlying metatarsels andtoes of a wearer; (b) a common stretch layer attached to each of saidfoundation layers and having portions of elastic stretchable materialunderlying said stretch chambers of a respective one of said foundationlayers; and (c) a pair of thrustor layers each attached to said stretchlayer and having portions of stiff material underlying and aligned witha respective one of said pluralities of said stretch chambers of saidfoundation layers and with said portions of said stretch layer disposedbetween said thrustor layers and foundation layers such thatinteractions can occur between said respective ones of said foundationlayers, stretch layers, and thrustor layers of said metatarsel and toeregions of said sole in response to compressive forces applied theretoupon contact of said metatarsel and toe regions of said sole with asupport surface that convert and temporarily store energy applied tosaid metatarsel and toe regions of said sole by a wearer's foot intomechanical stretching of said portions of said respective stretch layersinto said stretch chambers, said stored applied energy thereafter beingretrieved in the form of rebound of said stretched portions of saidrespective stretch layers and portions of said respective thrustorlayers therewith.
 22. The sole of claim 21 wherein said respectivestretch chambers of said metatarsel and toe regions of said sole are solocated to provide said temporary storage and retrieval of appliedenergy at independent sites underlying the individual metatarsals andtoes of a wearer's foot.
 23. The sole of claim 21 wherein said solefurther comprises: a pair of articulated plates each substantially flatand made of a stiff material, each of said plates having a plurality oflaterally spaced slits formed therein extending from a forward edgesrearwardly to midway between said forward edges and rearward edges ofsaid articulated plates, said pluralities of spaced slits definingindependent deflectable appendages on said respective articulated platesthat correspond to the individual metatarsels and toes of the wearer'sfoot and overlie the respective independent stetch chambers fortemporary storage and retrieval of the applied energy at the individualmetatarsals and toes of the wearer's foot.
 24. The sole of claim 23wherein said articulated plates, foundation layers, common stretch layerand thrustor layers are provided in the aforesaid sequence in respectivevertically stacked arrangements in said metatarsel and toe regions ofsaid sole with said articulated plates located closest to said upper ofsaid footwear and said thrustor layer located farthest from said upperof said footwear.
 25. The sole of claim 21 wherein said plurality ofstretch chambers are interconnected interior slots formed in saidfoundation layer and having portions matched to the metatarsels and toesof the wearer's foot.
 26. The sole of claim 21 wherein each of saidthrustor layers includes a thrustor plate having a peripheral profilematching that of said interconnected interior slots in a respective oneof said foundation layers and attached to a bottom surface of arespective central portion of said common stretch layer in alignmentwith said interior slots in said respective one foundation layer suchthat upon compression of said thrustor layers toward said foundationlayers from a relaxed condition toward a loaded condition of said sole,as occurs upon impact of said metatarsel and toe regions of said sole ofsaid footwear with the support surface during normal activity, saidcentral portions of said common stretch layer are forceably stretched bysaid thrustor plates upwardly into said stretch chambers underlying saidmetatarsels and toes of the wearer's foot.
 27. The sole of claim 26wherein each of said thrustor layers further includes a thrustor capattached on a bottom surface of said thrustor plate and made of aflexible material, said thrustor cap having a thickness selected to atleast partially determine depth of penetration and length of drive andrebound of said respective thrustor plates.
 28. The sole of claim 27wherein each of said thrustor layers further includes a retainer ringsurrounding said respective thrustor plate and thrustor cap, saidretainer ring being attached to a bottom surface of said common stretchlayer outside of said periphery of and surrounding said thrustor plateso as to increase the stretch resistance of said respective centralportion of said common stretch layer and stabilize said thrustor layersin a horizontal plane reducing the potential of binding of said thrustorplates as they stretch said respective central portions of said commonstretch layer through said slots in said respective foundation layersand into said stretch chambers underlying the metatarsels and toes ofthe wearer's foot.